TOKYO • As US satellite data suggests North Korea may have begun fuelling a rocket it plans to launch this month, Japanese and South Korean airlines say they will be rerouting a number of flights during the launch window period.
North Korea "will finish preparations for the launch as soon as the next several days", an unidentified US Defence Department official told Japanese newspaper Asahi Shimbun.
Since Thursday, satellite images have shown increased movement of people and equipment around a launch pad and a fuel storehouse at North Korea's Sohae satellite launch complex in the country's north-west, the official said.
The United States judged that fuelling appears to have started as it has been monitoring Pyongyang's movements via military intelligence satellites which can analyse objects as small as 30cm, the official said.
Given the difficulty in stopping the process once fuelling begins, preparation work normally finishes within several days of that, the official told the Asahi.
Pyongyang has announced that it will launch a satellite-bearing rocket between Feb 8 and Feb 25.
In its formal notification sent to United Nations agencies, North Korea provided flight coordinates similar to those of its last successful launch, of a three-stage Unha-3 rocket in December 2012.
The separated first stage was predicted to fall in the Yellow Sea off the west coast of South Korea, followed by a second-stage splashdown in the Philippine Sea.
To avoid any possible collision, Japanese and South Korean airlines will be rerouting some flights.
Japan's two biggest airlines - All Nippon Airways and Japan Airlines - said they would be diverting planes that fly over waters off the Philippines.
The change will affect three ANA flights - from Tokyo's Haneda airport to Manila, from Manila to Tokyo's Narita International Airport, and from Jakarta in Indonesia to Narita.
Two JAL flights - one from Jakarta to Narita and another from Narita to Manila - will also be rerouted.
South Korea's Transport Ministry said a total of 39 flights to and from the southern resort island of Jeju will be rerouted, involving the country's two main carriers, Korean Air and Asiana Airlines, as well as some Chinese carriers. Another 36 flights from Korean Air and Asiana will adjust their routes to avoid waters off the Philippines.
An SIA spokesman said "Singapore Airlines flight paths will avoid the affected region during the test window period".
The US has deployed missile defence systems that will work with the Japanese and South Korean militaries to track the rocket.
China has told North Korea that it does not want to see anything happen that could further raise tensions, Chinese Foreign Minister Wang Yi said, describing "a serious situation", after its special envoy for the nuclear issue Wu Dawei visited North Korea this week.
AGENCE FRANCE-PRESSE, REUTERS